UMAT example

[mambo5]

hi,

is that any good books, documents which i could refer to. I would like to write a UMAT subroutine which i want to define myown material properties (stress-strain curves etc.). I am new in Fortran, I not really understand how the subroutine work in ABAQUS. please advise.

 

[xerf]

You should check:

Abaqus Documentation ->ABAQUS User Subroutines Reference Manual ->1.1.31 UMAT

The section above includes an example.

I just want to point out that coding UMAT (meaningfully) may be non-trivial, ranging from several lines for linear elasticity to thousands of lines for complex contitutive behaviors (e.g., crystal plasticity).

Understanding of continuum mechanics is almost mandatory.

A good introductory book, written in context of software ABAQUS, is "Introduction to Computational Plasticity" by by Fionn Dunne and Nik Petrinic

A more advanced and well known book is "Computational Inelasticity" by Simo and Hughes.

Another book: "Inelastic Analysis of Solids and Structures" by Kojic and Bathe. I think this book is directly related to the software ADINA (owned by Prof. KJ Bathe from MIT).

Most of the important textbooks dealing with non-linear FE have chapters on theoretical and implementation aspects of constitutive reponses in FEM(i.e. coding UMAT or similar subroutines).